In many medical procedures, a needle is used to penetrate the patient's skin to either inject medicaments or other fluids into the patient or to withdraw blood from a patient. For example, a hypodermic syringe may be used to inoculate a patient or to administer other drugs to a patient, a blood collection set having a blood collection needle attached thereto may be inserted into a patient's vasculature to obtain a blood sample from the patient, or an intravenous (IV) catheter may be inserted into a patient's vasculature via an introducer needle to provide continued access to a patient's vasculature for the administration of various fluids or medicaments to the patient. Other medical procedures requiring the use of a needle include sewing broken skin together to facilitate the repair of the skin after a major cut in the skin. In addition to needles that penetrate a patient's skin, a sharp scalpel may be used in other medical procedures to cut the skin so a physician can remove unwanted tissue or to provide access to a portion of the patient's body below the skin.
The skin acts as a barrier to prevent microorganisms from entering the body of the patient. Typically the skin contains a multiplicity of microorganisms thereon. As long as the skin surface is intact, the microorganisms generally present no problem to the patient. However, when a medical procedure is performed on a patient, such as one of the procedures decribed above, the natural barrier formed by the skin is breached providing a pathway for microorganisms to enter the body. Such microorganisms can cause serious infection to a patient and, if left untreated, could result in death to the patient. Thus it is important to prevent these microorganisms from entering the body. Various protocols to reduce or eliminate skin microorganisms have been developed and are generally practiced rigorously prior to the performance of any of the medical procedures outlined above. The protocols generally involve a thorough swabbing of the skin surface with an appropriate antimicrobial agent such as isopropyl alcohol, an iodophor or polyvinylpyrrolidone iodine.
In addition to the need to prevent the ingress of microorganisms into the body via an opening in the skin created during a medical procedure, maintaining patient comfort during a medical procedure is also a legitimate concern for the caregiver. All of the medical procedures outlined above can be performed without the use of an anesthetic. However, these procedures can be uncomfortable and even quite painful to the patient. Various anesthetic compositions are available and are typically delivered to the patient via a hypodermic syringe. Obviously, for patients who feel exceptional discomfort having a needle inserted into them, the use of a hypodermic needle to deliver a dose of anesthetic is undesirable.
Recently, anesthetics that can be delivered to the patient topically have become commercially available. One problem with these topical anesthetics is the time delay between application and the onset of "numbness". If the delay is too long, the medical personnel will have to waste valuable time waiting for the anesthetic to take effect before the medical procedure can begin. If the patient has to apply the anesthetic, the patient will be required to handle the anesthetic carefully to prevent contamination, and apply the anesthetic properly and to the appropriate part of the body where the medical procedure will take place. In addition, the patient will have to carefully note the time when the anesthetic is applied to ensure that the anesthetic is still effective during the entire medical procedure.
Another concern relating to such topical anesthetics is whether the effect of the anesthetic will extend significantly below the skin surface. Because the skin is an effective barrier to the entry of microorganisms into a patient's body, it is difficult to get medical agents to penetrate the skin effectively without irritating or otherwise damaging the skin. If the anesthetic does not effectively penetrate the skin, the patient would still feel discomfort or pain from certain medical procedures where a needle or scalpel penetrated the patient's body below the skin a significant distance. To remedy this problem there has been work done to identify appropriate chemical penetration enhancers to facilitate transdermal drug delivery.
Anti-microbial agents and topical anesthetics are typically applied separately with some type of cotton swab separately used to apply each substance. Unfortunately, there is currently no single device that can apply both the anti-microbial agent and the topical anesthetic to the patient. Such a device would be desireable because it would facilitate the application of both the anti-microbial agent and the topical anesthetic so the patient would enjoy the benefits of both. In addition, significant time could be saved by using a single device to apply both the anti-microbial agent and the topical anesthetic.